1. Field of the Invention
This invention is directed to methods and apparatuses for making optical sensors and to optical sensors. In one specific aspect, this invention is directed to multi-fiber fiber optic sensors and to methods for making them. In one specific aspect, this invention is directed to multi-fiber fiber optic sensor probes for sensing blood gas levels in vivo. In another aspect multiple sensors are used in one catheter-like probe.
2. Background of the Invention
In 1985, David Costello, one of the co-inventors named in this application, filed his application entitled "Fiber Optic Probe For Quantification of colorimetric Reactions" which resulted in the issuance of U.S. Pat. No. 4,682,895. This patent claims an optical sensor for the colorimetric measurement of chemical properties which can be inserted into living tissue, e.g. into the blood vessels of a human being. This optical probe allows arterial blood gases to be monitored within a patient with a fiber optic sensor placed through an arterial cannula or arterial line, whereas before values for such gases were measured in a laboratory in blood samples taken from the patient.
With the new sensor, real-time determination of a biochemical parameter or blood gas value is possible, providing up-to-the minute information to a physician. This can be of critical importance with an unstable patient whose biochemical parameters and blood gases may change dramatically over a short period of time. Real-time current and trend information is much more valuable to a physician than the previously-available discrete historical data.
In addition to the unique fiber optic probe of U.S. Pat. No. 4,682,895, other fiber optic sensor designs are available. One such design uses a reflection-based optical path (Peterson & Goldstein) In another design a fluormetric indicator system is employed (Vurek; Munkolm & Watt; Lubbers). Devices incorporating these designs have been made using extrusion/insertion techniques or co-extrusion techniques. Incorporated fully herein by reference is "Chemical Sensors Based On Immobilized Indicators And Fiber Optics," by W. Rudolf Seitz from CRC Critical Reviews in Analytical Chemistry, Vol. 19, Issue 2, 1988 which describes various prior art fiber optic sensors.
There has long been a need for a reliable and efficient process for the production of fiber optic sensors and multi-sensor probes. There has long been a need for a multiple sensor device and efficient and reliable methods for its production. There has long been a need for an automated process for producing multi-fiber optic sensors. There has long been a need for such a probe which can be easily introduced into small tubes, e.g. blood vessels. There has long been a need for a fiber optic sensor in which multiple optical fibers have a precise arrangement, and a need for a process for making such sensors.